HP Notebook power scrambled

The video brightness on my HP Pavilion notebook is bass ackwards. When I am on the power cord, the screen intensity dims (presumably the power saver mode) and when I'm on battery it brightens. I get just about 1.5 hours of useful time on a battery charge. A friend's identical notebook works correctly. I've seen other brand notebooks with a switch that could be changed by doing an F8 on startup and making some adjustments. I don't see that on mine. How can I fix this?

 

After not getting a reply on several forums I think I realized that this is a very uncommon problem. I just got offline with the HP technician chat and she fixed it for me. This model remembers the brightness setting for battery and AC power. All I had to do was adjust the brightness for the battery setting when it was on battery and readjust it brighter for AC when it was on the AC power.